Core/Auras: Fix hunter periodic damage critical bonus calculation

[gonzo1247]

Changes proposed:

Certain Hunter periodic spells (e.g. Serpent Sting, Black Arrow) were using the melee/ranged critical damage baseline (200%) due to being classified with SPELL_DAMAGE_CLASS_RANGED.

However, these spells are periodic in nature and should follow the magical critical damage baseline (150%), as intended by game mechanics.

Because of this, talents like Toxicology (82832 / 82833), which increase critical damage of these effects by 50% / 100%, had little to no effect, since the spells were already dealing 200% critical damage by default.

This change ensures that:

• Hunter periodic spells use the correct magical critical damage baseline (150%)
• SPELLMOD_CRIT_DAMAGE_BONUS correctly scales the crit bonus portion
• Talents like Toxicology now properly increase critical damage as intended

Example:
Before:

• Base crit: 200%
• Toxicology had no effective impact

After:

• Base crit: 150%
• Toxicology increases crit damage to 200% / 250% as expected

IsReducedPeriodicCritDamageSpell is used to explicitly identify Hunter periodic spells that should use the reduced periodic critical damage baseline (150%).

These spells are flagged as SPELL_DAMAGE_CLASS_RANGED and would normally follow the 200% melee/ranged critical damage path. However, they are intended exceptions and should instead use the reduced 150% baseline.

A generic solution is not feasible here, as there are no reliable shared attributes that distinguish these spells without introducing unintended side effects. Therefore, an explicit spell-based check is used to ensure correct behavior.

Tests performed: (Does it build, tested in-game, etc)
Build has been tested in-game using the Toxicology talent (82832 / 82833), both with and without it.

Results:

• Without talent: periodic critical damage correctly uses the 150% magical baseline
• With talent: SPELLMOD_CRIT_DAMAGE_BONUS properly increases the crit bonus portion

This confirms that Toxicology now correctly affects Serpent Sting and Black Arrow as intended.